JP6956777B2 - Piecewise alignment modeling method - Google Patents

Description

The embodiments of the present disclosure generally relate to the field of maskless lithography. More specifically, the embodiments provided herein relate to systems and methods for adjusting substrate exposure parameters according to overlay errors.

Photolithography is widely used in the manufacture of semiconductor devices and display devices such as liquid crystal displays (LCDs). Large area substrates are often used in the manufacture of LCDs. LCDs or flat panels are commonly used in active matrix displays such as computers, touch panel devices, personal digital assistants (PDAs), mobile phones, television monitors, and the like. Generally, a flat panel may include a layer of liquid crystal material that forms a pixel sandwiched between two plates. When the power from the power source is applied over the entire liquid crystal material, the amount of light passing through the liquid crystal material is controlled at the pixel position, which may enable the generation of an image.

Microlithography techniques are commonly used to create electrical features that are incorporated as part of the liquid crystal material layer that forms the pixels. This technique typically applies a photosensitive photoresist to at least one surface of the substrate. The pattern generator then irradiates regions of the photosensitive photoresist selected as part of the pattern with light to cause a chemical change in the photoresist within the selected regions, producing electrical features in these selected regions. Prepare for the subsequent process of material removal and / or material addition to produce.

A new device that creates patterns accurately and with good cost performance on substrates such as large-area substrates in order to continuously provide display devices and other devices to consumers at the price demanded by consumers. Techniques and systems are needed.

The embodiments disclosed herein generally relate to adjusting the exposure parameters of the substrate depending on the overlay error. The method comprises dividing the substrate into multiple compartments. Each compartment corresponds to an image projection system. The total overlay error of the first layer deposited on the substrate is determined. The superposition error of the parcels is calculated for each parcel. The average superposition error is calculated for each overlapping region where two or more compartments overlap. The exposure parameters are adjusted according to the total overlay error.

In another embodiment, a computer system for adjusting the exposure parameters of the substrate according to the total superposition error is disclosed herein. A computer system includes a processor and memory. The memory stores instructions that, when executed by the processor, cause the processor to execute a method of adjusting exposure parameters to the substrate according to overlay error. The method comprises dividing the substrate into multiple compartments. Each compartment corresponds to an image projection system. The total overlay error of the first layer deposited on the substrate is determined. The superposition error of the parcels is calculated for each parcel. The average superposition error is calculated for each overlapping region where two or more compartments overlap. The exposure parameters are adjusted according to the total overlay error.

In yet another embodiment, a non-transitory computer-readable medium is disclosed herein. The non-temporary computer-readable medium, when executed by the processor, stores instructions that cause the computer system to adjust the exposure parameters of the substrate according to the overlay error by performing the steps of the method. The method comprises dividing the substrate into multiple compartments. Each compartment corresponds to an image projection system. The total overlay error of the first layer deposited on the substrate is determined. The superposition error of the parcels is calculated for each parcel. The average superposition error is calculated for each overlapping region where two or more compartments overlap. The exposure parameters are adjusted according to the total overlay error.

More specific description of the present disclosure outlined above can be obtained by reference to embodiments so that the above-mentioned features of the present disclosure can be understood in detail, some of which are shown in the accompanying drawings. There is. However, as the present disclosure may apply to other equally valid embodiments, the accompanying drawings merely illustrate exemplary embodiments of the present disclosure and are therefore considered to limit the scope of the present disclosure. Note that it should not be.

FIG. 5 is a perspective view of a system that may benefit from the embodiments disclosed herein. It is a schematic perspective view of a plurality of image projection systems according to one embodiment. The beam reflected by the two mirrors of the DMD according to one embodiment is shown schematically. It is a perspective view of the image projection apparatus according to one Embodiment. A computer system according to an embodiment is shown. A more detailed view of the server of FIG. 5 according to one embodiment is shown. The controller calculation system according to one embodiment is shown. The steps of the method for adjusting the exposure parameters of the substrate according to the overlay error are shown schematically. A top view of a substrate having a first layer deposited on it according to one embodiment is shown.

For ease of understanding, the same reference numbers were used to point to the same elements that are common to multiple figures, where possible. It is assumed that the elements and features of one embodiment can be beneficially incorporated into other embodiments without further description.

The embodiments disclosed herein generally relate to adjusting the exposure parameters of the substrate depending on the overlay error. The method comprises dividing the substrate into one or more compartments. Each compartment corresponds to an image projection system. The total overlay error of the first layer deposited on the substrate is determined. The superposition error of the parcels is calculated for each parcel. The average superposition error is calculated for each superposition area where two or more compartments overlap. The exposure parameters are adjusted according to the total overlay error.

As used herein, the term "user" refers, for example, to the person or subject who owns the computing device or wireless device, the person or subject who operates or uses the computing device or wireless device, or otherwise. Includes a person or subject associated with a computing or wireless device. The term "user" is not intended to be limiting and it is assumed that it may include various examples beyond those described.

FIG. 1 is a perspective view of a system 100 that may benefit from the embodiments disclosed herein. The system 100 shown in the cross section includes a base frame 110, a slab 120, two or more stages 130, and a processing device 160. In certain embodiments, one stage 130 may be used. The base frame 110 may be placed on the floor of the manufacturing facility to support the slab 120. The passive air isolator 112 may be positioned between the base frame 110 and the slab 120. The slab 120 is a single plate of granite, and two or more stages 130 can be placed on top of the slab 120. The substrate 140 may be supported by each of two or more stages 130. Multiple holes (not shown) may be formed in the stage 130, which allows multiple lift pins (not shown) to extend through those holes. The lift pin can be raised to an extended position, for example to receive the substrate 140 from a transfer robot (not shown). The transfer robot positions the substrate 140 on the lift pin, which can then gradually lower the substrate 140 onto the stage 130.

The substrate 140 is made of, for example, quartz and can be used as part of a flat panel display. In other embodiments, the substrate 140 may be made of other materials. In some embodiments, the substrate 140 may have a photoresist layer formed on it. The photoresist is sensitive to radiation and can be a positive photoresist or a negative photoresist. That is, each portion of the photoresist exposed to radiation will be soluble or insoluble in the photoresist developer, which is applied to the photoresist after the pattern has been written to the photoresist. The chemical composition of the photoresist determines whether the photoresist is a positive photoresist or a negative photoresist. For example, the photoresist may contain at least one of diazonaphthoquinone, phenol formaldehyde resin, poly (methylmethacrylate), poly (methylglutarimide), and SU-8. Thus, a pattern can be created on the surface of the substrate 140 to form an electronic circuit.

The system 100 may further include a pair of supports 122 and a pair of trajectories 124. The pair of supports 122 are arranged on the slab 120, and the slab 120 and the pair of supports 122 can be a single piece of material. The pair of orbits 124 are supported by a pair of supports 122, and the two or more stages 130 can move in the X direction along the orbits 124. In one embodiment, the pair of orbits 124 is a pair of parallel magnetic channels. As shown, each orbit 124 of the pair of orbits 124 is linear. In other embodiments, the orbit 124 may have a non-linear shape. Encoders 126 may be coupled to each stage 130 to provide location information to controller 702 (see FIG. 7).

The processing device 160 may include a support 162 and a processing unit 164. The support 162 is placed on top of the slab 120 and may include an opening 166 for two or more stages 130 to pass under the processing unit 164. The processing unit 164 can be supported by a support 162. In one embodiment, the processing unit 164 is a pattern generator configured to expose the photoresist in a photolithography process. In some embodiments, the pattern generator may be configured to perform maskless lithography. The processing unit 164 may include a plurality of image projection systems (shown in FIG. 2) arranged within the housing 165. The processing apparatus 160 can be used to perform maskless direct patterning. During operation, one of the two or more stages 130 moves in the X direction from the carry-in position shown in FIG. 1 to the processing position. The processing position may refer to one or more positions of the stage 130 as the stage 130 passes under the processing unit 164. During operation, the two or more stages 130 can be raised by the plurality of air bearings 200 and moved from the carry-in position to the processing position along the pair of tracks 124. In order to stabilize the movement of the stage 130, a plurality of vertical guide air bearings (not shown) may be connected to each stage 130 and positioned adjacent to the inner wall 128 of each support 122. Each of the two or more stages 130 can also move in the Y direction by moving along the orbit 150 for processing and / or indexing of the substrate 140.

As shown, each stage 130 includes a plurality of air bearings 200 for raising the stage 130. Each stage 130 may also include a motor coil (not shown) for moving the stage 130 along the track 124. Two or more stages 130 and processing equipment 160 may be enclosed by an enclosure (not shown) to control temperature and pressure.

FIG. 2 is a schematic perspective view of a plurality of image projection systems 301 according to one embodiment. As shown in FIG. 2, each image projection system 301 generates a plurality of write beams 302 on the surface 304 of the substrate 140. As the substrate 140 moves in the X and Y directions, the entire surface 304 can be patterned by the write beam 302. The number of image projection systems 301 can vary based on the size of the substrate 140 and / or the speed of the stage 130. In one embodiment, there are 22 image projection systems 301 in the processing apparatus 160.

The image projection system 301 may include a light source 402, an opening 404, a lens 406, a mirror 408, a DMD 410, an optical dump 412, a camera 414, and a projection lens 416. The light source 402 is a light emitting diode (LED) or a laser and may be capable of producing light having a predetermined wavelength. In one embodiment, the predetermined wavelength is within the blue or near-ultraviolet (UV) range, such as less than about 450 nm. The mirror 408 can be a spherical mirror. The projection lens 416 can be a 10x objective lens. The DMD 410 includes a plurality of mirrors, the number of mirrors of which can correspond to the resolution of the projected image. In one embodiment, the DMD 410 comprises a 1920 x 1080 mirror.

During operation, the light source 402 produces a beam 403 having a predetermined wavelength, such as a wavelength within the blue range. The beam 403 is reflected by the mirror 408 on the DMD 410. The DMD410 includes a plurality of mirrors that can be individually controlled, and each mirror of the plurality of mirrors of the DMD410 is in an "on" position or based on mask data provided to the DMD410 by a controller (not shown). It can be in the "off" position. When the beam 403 reaches the mirror of the DMD 410, the mirror in the "on" position reflects the beam 403 towards the projection lens 416, i.e. forming a plurality of write beams 302. The projection lens 416 then projects the write beam 302 onto the surface 304 of the substrate 140. The mirror in the "off" position reflects the beam 403 towards the light dump 412 instead of the surface 304 of the substrate 140.

In one embodiment, the DMD 410 may have more than one mirror. Each mirror can be placed on a tilt mechanism that can be placed on a memory cell. The memory cell can be a CMOS SRAM. During operation, each mirror is controlled by reading mask data into a memory cell. The mask data electrostatically controls the tilt of the mirror in binary. When the mirror is in reset mode or when no power is applied, the mirror can be set to a flat position that does not correspond to any binary number. Zero in binary can correspond to the "off" position. That is, the mirror is tilted to -10 degrees, -12 degrees, or any other feasible negative tilt. The 1 in binary can correspond to the "on" position. That is, the mirror is tilted at +10 degrees, +12 degrees, or any other feasible positive tilt.

FIG. 3 schematically shows the beam 403 reflected by the two mirrors 502, 504 of the DMD 410. As shown, the mirror 502 in the "off" position reflects the beam 403 generated by the light source 402 onto the light dump 412. The mirror 504 in the "on" position forms the write beam 302 by reflecting the beam 403 towards the projection lens 416.

Each system 100 includes an arbitrary number of image projection systems 301, and the number of image projection systems 301 can vary from system to system. In one embodiment, there are 84 image projection systems 301. Each image projection system 301 may include 40 diodes, or any number of diodes. Higher power is required to handle such a large number of diodes, which causes problems when trying to maintain a large number of diodes. One solution could be to align the diodes in series, but when configured in series, it is necessary to detect non-functional diodes, as described below.

FIG. 4 is a perspective view of the image projection device 390 according to the embodiment. The image projection device 390 is used to focus light on a spot on the plane of the substrate 140 and finally project an image onto the substrate 140. The image projection device 390 includes two subsystems. The image projection device 390 includes a lighting system and a projection system. The lighting system includes at least an optical pipe 391 and a white light illumination device 392. The projection system includes at least DMD410, frastrated prism assembly 288, beam splitter 395, one or more projection optics 396a, 396b, distortion compensator 397, focus motor 398, and projection lens 416 (described above). .. The projection lens 416 includes a focus group 416a and a window 416b.

Light is introduced from the light source 402 to the image projection device 390. The light source 402 may be a chemical ray light source. For example, the light source 402 may be a bundle of fibers, each fiber containing one laser. In one embodiment, the light source 402 may be a bundle of about 100 fibers. The bundle of fibers may be irradiated by a laser diode. The light source 402 is connected to an optical pipe (or Kaleido) 391. In one embodiment, the light source 402 is connected to the optical pipe 391 via a coupler that couples each of the bundled fibers.

Once the light from the light source 402 enters the optical pipe 391, the light is homogenized when it exits the optical pipe 391, and the light bounces inside the optical pipe 391 so as to be uniform. In one embodiment, the light may bounce up to 6 or 7 times in the optical pipe 391. In other words, the light undergoes a total of 6-7 internal reflections within the optical pipe 391, resulting in a uniform light output.

The image projection device 390 may optionally include various reflective surfaces (unsigned). The various reflective surfaces capture a portion of the light traveling through the image projection device 390. In one embodiment, the various reflective surfaces can help capture some light and then direct the light to the light level sensor 393, and the laser level can be monitored.

The white light illumination device 392 projects broadband visible light onto the projection system of the image projection device 390. In particular, the white light illumination device 392 directs light to the frustrated prism assembly. The chemical ray light source and the wideband light source can be turned on and off independently of each other.

The frustrated prism assembly 288 functions to supply the light that will be projected onto the surface of the substrate 140. With the frustrated prism assembly 288, all of the internally reflected light is emitted, minimizing energy loss. The frustrated prism assembly 288 is coupled to a beam splitter 395.

The DMD410 is included as part of the frustrated cube assembly. The DMD 410 is a pattern generation device of the image projection device 390. The use of the DMD 410 and the frustrated prism assembly 288 increases the footprint of each image projection device 390 by keeping the direction of the illumination flow approximately perpendicular to the substrate 140 from the light source 402 that produces the exposure illumination to the substrate focal plane. Helps to minimize.

The beam splitter 395 is used to further extract a portion of the light reflected from the substrate 140 for alignment. More specifically, the beam splitter 395 is used to split the light into two separate beams. The beam splitter 395 is coupled to the projection optical system 396. Two parts of the projection optics 396a and 396b are shown in FIG.

In one embodiment, the focus sensor and camera 284 are attached to the beam splitter 395. The focus sensor and camera 284 are configured to monitor the imaging quality of various aspects of the image projection device 390, including but not limited to focus lens focus and alignment through the lens, and mirror tilt angle variation. Can be done. In addition, the focus sensor and camera 284 may indicate an image to be projected onto the substrate 140. In a further embodiment, the focus sensor and camera 284 can be used to capture images on the substrate 140 and make comparisons between those images. In other words, the focus sensor and camera 284 can be used to perform inspection functions.

The projection optics 396, distortion compensator 397, focus motor 398, and projection lens 416 work together to prepare a pattern and finally project the pattern from the DMD 410 onto the substrate 140. The projection optical system 396a is coupled to the strain compensator 397. The distortion compensator 397 is coupled to the projection optical system 396b, and the projection optical system 396b is coupled to the focus motor 398. The focus motor 398 is coupled to the projection lens 416. The projection lens 416 includes a focus group 416a and a window 416b. The focus group 416a is coupled to the window 416b. The window 416b may be replaceable.

The optical pipe 391 and the white light illumination device 392 are coupled to the first mounting plate 341. In addition, in embodiments that include additional various reflective surfaces (unsigned) and light level sensor 393, the various reflective surfaces and light level sensor 393 may also be coupled to the first mounting plate 341.

The frustration prism assembly 288, beam splitter 395, one or more projection optics portions 396a, 396b and strain compensator 397 are coupled to a second mounting plate 399. The first mounting plate 341 and the second mounting plate 399 are flat surfaces, which enables accurate alignment of the above components of the image projection device 390. In other words, the light passes through the image projection device 390 along a single optical axis. This precise alignment along a single optical axis results in a compact device. For example, the image projection device 390 can have a thickness between about 80 mm and about 100 mm.

FIG. 5 shows a calculation system 700 according to one embodiment. As illustrated, the compute system 700 includes multiple servers 708, overlay error application servers 712, and multiple controllers (ie, computers, personal computers, mobile / wireless devices) 702 (for clarity, of which. Only two are shown), but each is connected to a communication network 706 (eg, the Internet). The server 708 may communicate with the database 714 over a local connection (such as a storage area network (SAN) or network attached storage (NAS)) or over the Internet. The server 708 is configured to either directly access the data contained in the database 714 or interface with a database manager configured to manage the data contained in the database 714.

Each controller 702 receives and / or displays outputs as well as input devices such as processors, system memory, hard disk drives, batteries, mice and keyboards, and / or output devices such as monitors or graphical user interfaces. It can include traditional components of computing devices, such as combined input / output devices such as touch screens. Each server 708 and overlay error application server 712 manages the content stored in the database 714, including a processor and system memory (not shown) and using the relevant database software and / or file system. Can be set as The server 708 may be programmed to communicate with each other using a network protocol, such as the TCP / IP protocol, with the controller 702 and the overlay error application server 712. The overlay error application server 712 can communicate directly with the controller 702 through the communication network 706. Controller 702 accesses an application that is programmed to run software 704, such as a program and / or other software application, and is managed by server 708.

In the embodiments described below, the user can operate each of the controllers 702 that can be connected to the server 708 through the communication network 706. Pages, images, data, documents, etc. may be displayed to the user via the controller 702. Information and images can be displayed through a display device communicating with controller 702 and / or a graphical user interface.

Controller 702 is a component suitable for communication with a personal computer, a laptop portable computing device, a smartphone, a video game controller, a home digital media player, a network-connected TV, a set-top box, and / or a communication network 706. Note that and / or other computing devices with the required application or software. The controller 702 may also execute other software applications configured to receive content and information from the board alignment application server 712.

FIG. 6 shows a more detailed view of the overlay error application server 712 of FIG. The overlay error application server 712 includes, but is not limited to, a central processing unit (CPU) 802, a network interface 804, a memory 820, and a storage 830 that communicate via the interconnect (interconnect) 806. The overlay error application server 712 may also include an I / O device interface 808 that connects to an I / O device 810 (eg, keyboard, video, mouse, audio, touch screen, etc.). The overlay error application server 712 may further include a network interface 804 configured to transmit data over the communication network 706.

The CPU 802 reads and executes the programming instructions stored in the memory 820, and usually controls and cooperates with the operations of other system components. Similarly, the CPU 802 stores the application data in the memory 820 and reads out the application data in the memory 820. Typically, a CPU 802 is included, which is a single CPU, a plurality of CPUs, a single CPU having a plurality of processing cores, and the like. The interconnect 806 is used to transmit programming instructions and application data between the CPU 802, the I / O device interface 808, the storage 830, the network interface 804, and the memory 820.

A memory 820, typically a random access memory, is typically included, which stores software applications and data used by the CPU 802 during operation. Storage 830, illustrated as a single unit, is a fixed disk drive, floppy disk drive, hard disk drive, flash memory storage drive, tape drive, removable memory configured to store non-volatile data. Fixed storage devices and / or removable, such as cards, CD-ROMs, DVD-ROMs, Blu-Rays, HD-DVDs, optical storage, networked storage (NAS), cloud storage, or storage area networks (SAN). It can be a combination of storage devices.

The memory 820 may store instructions and logic for executing the application platform 826 including the overlay error software 828. Storage 830 may include database 832 configured to store data 834 and associated application platform content 836. Database 832 can be any type of storage device.

A network computer is another type of computer system that can be used in conjunction with the disclosures presented herein. Network computers typically do not include hard disks or other large storage, and executable programs are loaded into memory 820 from a network connection for execution by CPU 802. A typical computer system will generally include at least a processor, memory, and an interconnect that binds the memory to the processor.

FIG. 7 shows a controller 702 used to access the overlay error application server 712 and read or display data associated with the application platform 826. The controller 702 may include, but is not limited to, a central processing unit (CPU) 902, a network interface 904, an interconnect 906, a memory 920, a storage 930, and a support circuit 940. The controller 702 may also include an I / O device interface 908 that connects the I / O device 910 (devices such as keyboards, displays, touch screens, and mice) to the controller 702.

Similar to the CPU 802, a CPU 902 is typically included, such as a single CPU, a plurality of CPUs, and a single CPU having a plurality of processing cores, and a memory 920, which is a random access memory, is generally used. included. The interconnect 906 can be used to transmit programming instructions and application data between the CPU 902, the I / O device interface 908, the storage 930, the network interface 904, and the memory 920. The network interface 904 may be configured to transmit data over the communication network 706, for example, to transfer content from the surface alignment application server 712. Storage 930, such as a hard disk drive or solid state storage drive (SSD), may store non-volatile data. Storage 930 may include database 931. Database 931 may include data 932 and other content 934. In some embodiments, the database 931 may further include an image processing unit 936. The image processing unit may include data 938 and / or control logic 939. Illustratively, the memory 920 includes an application interface 922, which itself may display software instructions 924 and / or store or display data 926. The application interface 922 may provide one or more software applications that allow the controller 702 to access data and other content hosted by the surface alignment application server 712.

Controller 702 may be coupled or communicate with one or more of processing apparatus 160, stage 130, and encoder 126. The processing apparatus 160 and the stage 130 may provide information to the controller 702 regarding substrate processing and substrate alignment. For example, the processing apparatus 160 may provide information to the controller 702 and warn the controller that the substrate processing is complete. The encoder 126 can provide position information to the controller 702, which position information is then used to control the stage 130 and the processing device 160.

The controller 702 may include a central processing unit (CPU) 902, a memory 920, and a support circuit 940 (or I / O 908). The CPU 902 is one of any form of computer processor and hardware (such as pattern generators, motors, and other hardware) used in industrial settings to control various processes and processes (such as pattern generators, motors, and other hardware). Processing time, board position, etc.) can be monitored. Memory 920 is connected to CPU 902 as shown in FIG. 7, and is connected to random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital. It can be one or more of the readily available memories, such as storage. Software instructions and data can be encoded and stored in memory for instructing the CPU 902. The support circuit 940 is also connected to the CPU 902 to support the processor in a conventional manner. The support circuit 940 may include a conventional cache 942, a power supply 944, a clock circuit 946, an input / output circuit 948, a subsystem 950, and the like. A readable program (or computer instruction) by controller 702 determines which tasks can be performed on the board. The program is readable software by controller 702 and may include, for example, code for monitoring and controlling processing time and board position.

However, it should be noted that all these terms and similar terms should be associated with appropriate physical quantities and are merely convenience codes applied to these quantities. As will be apparent from the discussion below, unless otherwise stated, "processing," "computing," "calculating," and "determining" throughout this specification. Or, a study using terms such as "displaying" manipulates the data represented as the physical (electronic) quantity in the computer system's register and memory, and the computer system's memory or register, or such. It is recognized to refer to the operation and process of a computer system or similar electronic computing device that transforms information into other data, which is also represented as a physical quantity in another storage device, transmission device, or display device.

The present embodiment also relates to an apparatus for performing the operations herein. The device may include a general purpose computer that may be specially constructed for the desired purpose, or may be selectively operated or reconstructed by a computer program stored in the computer. Such computer programs include read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, flash memory, magnetic or optical cards, floppy disks, optical disks, CD-ROMs, and magnetic-optical disks. Storage on a computer-readable storage medium, such as, but not limited to, any type of disk, or any type of medium suitable for storing electronic instructions, each of which is coupled to a computer system interconnect. Can be done.

The algorithms and displays presented herein are essentially unrelated to any particular computer or other device. It may be convenient to build more specialized equipment for various general purpose systems to perform the method steps used or required with the program according to the teachings herein. The structure of a wide variety of these systems will become apparent from the above description herein. In addition, the examples in the present disclosure are not described in the context of any particular programming language, and therefore various examples can be implemented using a variety of programming languages.

As described in more detail herein, embodiments of the present disclosure dither the edges of these features at forbidden angles to reduce edge placement errors during maskless lithography patterning during the manufacturing process. By processing, it provides a software application in which line wave defects of an exposed polygon are corrected by a forbidden angle.

In one embodiment, a method 1000 for adjusting exposure parameters according to the total superposition region is disclosed. Method 1000 can be performed by controller 702, as shown in FIG. 7 and relatedly described above. The CPU 902 is programmed to run the overlay error software 828 stored in memory 820, providing method 1000 for adjusting the exposure parameters according to the total overlay area, which is described below in connection with FIG. implement.

FIG. 8 schematically shows the steps of Method 1000 for adjusting the exposure parameters according to the total superposition region, as shown in FIG. Method 1000 generally relates to determining the total overlay error of the first layer deposited on the substrate and adjusting the exposure parameters according to the total overlay error. Between one layer and the next layer on top of the previous layer, the individual patterns of one layer and the next layer must be aligned. However, due to differences in patterns and materials in multiple layers on top of each other, variations in film stress and / or topography between layers (or pattern-related differences) are unavoidable. The film stress generated between the layers formed on the substrate deforms the substrate, affects the result of the lithography patterning process, and may lead to the problem of the device yield of the semiconductor device formed on the substrate. be. Superposition errors in the device structure can come from a variety of error sources. One of the commonly seen sources in this field is deformation of the substrate film layer caused by film stress, substrate curvature and the like. Membrane stress of the device structure on the substrate, curvature of the substrate, deformation of the substrate, or variation in surface topography can also result in displacement or misalignment of the lithography pattern formed from one layer to the next. , This can adversely affect the yield results of the device and / or cause variations in device performance. What starts out as an ideal rectangular shape can be a "pin-cushion" shape, where the substrate is pulled in various directions and no longer maintains the ideal rectangular shape. If the substrate is warped, the original center C may shift to the center C'. Therefore, a given point (x, y) with respect to the center can correspond to a point (x', y'). Therefore, in order to align subsequent layers on top of the first layer, the system needs to take into account the total overlay error.

Method 1000 begins in step 1002. In step 1002, the surface 1102 of the substrate 1101 is divided into one or more compartments _{S k.} One or more compartments _{S k} corresponds to one or more of the image projection system 301 in system 100. For example, given n image projection systems 301, the substrate 1101 will be divided into _{n compartments Sn.} In this example, the substrate 1101 is divided into four sections _S 1 -S ₄ corresponding to the configuration of the 2 × 2 image projection system 301. By dividing the substrate 1101 into one or more compartments S _k, thereby enabling more accurate reading of the overlay error. This is because a single optimal line may not be sufficient for complex strain patterns on the substrate. By dividing the substrate, it is possible to apply the optimum line to a smaller strain area, which allows the entire strain pattern to be read more accurately. When the substrate 1101 is divided into compartments, the origin (0,0) of each compartment is determined. Thus, the system is, in subsequent calculations, it is possible to more easily determine the center C of each compartment S ₁ -S _4.

In step 1004, the total overlay error of the first layer deposited on the substrate is determined. Determining the total overlay error includes determining the overlay error of compartments for each compartment S _k and (substep 1008), overlay overlapping the region where two or more compartments S _k overlap Includes determining the error (sub-step 1010).

ここで、方程式１は、ｘ方向の座標のシフトを表し、方程式２は、ｙ方向の座標のシフトを表す。方程式１と方程式２は、３つの成分、つまり、元の点（ｘ又はｙ）、

、及び

に分割される。Ｓ_ｋ（ｘ，ｙ）は、所与の区画Ｋを表し、ここでＳ_ｋ（ｘ，ｙ）は、区分関数であり、次のように表されうる。

点が区画Ｓ_ｋ内にない場合、区分関数Ｓ_ｋ（ｘ，ｙ）は、

をゼロにする。そのように、方程式３は、それぞれの区画内の点のみがその区画に対する最適な線を表す多項式によってシフトされることを保証する。他の区画は、異なる最適な線が使用される歪みパターンを示しうる。したがって、方程式１及び方程式２は、各区画について等価でないことがある。 In sub-step 1008, the overlay error of partition is determined for each section _{S k.} Error overlay section scans the upper surface of the first layer is first deposited on the substrate, it is determined by determining the amount of strain of each compartment S _k. The strain pattern is adapted to the trend line to determine the coordinate shift. For example, given a distortion with a linear pattern, the linear trend line can be used to determine how to adjust the process parameters for subsequent exposures. In another example, given a distortion that includes a curved distortion, the polynomial tendency line may be used to determine how to adjust the process parameters for subsequent exposures. In general, the trend line is the modified coordinates (x, y) in the modified process parameters (x', y') in the original process parameters to take into account the overlay error. Represents the polynomial to be transformed. In general, this can be expressed as:

Here, the equation 1 represents the shift of the coordinates in the x direction, and the equation 2 represents the shift of the coordinates in the y direction. Equation 1 and Equation 2 have three components: the original point (x or y),

,as well as

It is divided into. _Sk (x, y) represents a given partition K, where _Sk (x, y) is a piecewise function and can be expressed as:

If the point is not in the compartment _{S k,} piecewise function _S k (x, y) is

To zero. As such, Equation 3 ensures that only the points within each compartment are shifted by the polynomial that represents the optimal line for that compartment. Other compartments may show a distortion pattern in which different optimal lines are used. Therefore, equations 1 and 2 may not be equivalent for each compartment.

In the sub-step 1010, the overlap overlay error is determined. The overlap superposition error is determined in these regions where _{two or more compartments Sk overlap.} As shown in FIG. 9, the overlapping area _OA 1 -OA _5, it is a region where two or more compartments _{S k} overlap. In order to determine the overlay error in a given overlap region OA _k , the partition overlay error of the compartments that produce the _{overlap region OA k is averaged.} The shift in the x direction can be represented by Equation 4, and the shift in the y direction can be represented by Equation 5.

方程式６において、Ｓ_ｖ，Ｓ_ｗ∈Ｓ_ｋの場合、点（ｘ，ｙ）が少なくとも２つの区画Ｓ_ｖ，Ｓ_ｗの交点における要素であるという条件で、ＯＡ_ｋ（ｘ，ｙ）は、関数Ｗ_ｋ（ｘ，ｙ）を表す。点（ｘ，ｙ）が重なり領域内にある場合、関数Ｗ_ｋ（ｘ，ｙ）は、ＯＡ_ｋ（ｘ，ｙ）に対して方程式４及び方程式５に代入され、ここで、Ｗ_ｋ（ｘ，ｙ）は次のように表される。

ここで(ｃｘ_ｋ，ｃｙ_ｋ)は、各区画Ｓ_ｋの中心を定義する。 The overlapping region is _{represented by OA k} (x, y), where OA _k (x, y) is a divisional equation represented by the following equation 6.

In Equation _6, S v, when the _{S w} ∈S _k, the point (x, y) of at least two compartments _S v, with the proviso that an element at the intersection of _{S w,} OA k (x, y) is Represents the function W _k (x, y). If the points (x, y) are within the overlapping region, the function W _k (x, y) is _{assigned to equations 4 and 5 for OA k} (x, y), where W _k (x, y). , Y) is expressed as follows.

Here _{(cx k,} cy k) defines the center of each compartment _{S k.}

Each compartment S _k, and after calculating the shift of x and y for each point of all the overlapping area OA _k, in step 1006, exposure parameters, depending on the overlay error of the sum determined in step 1010 adjusts Will be done. For each point of each of the sections _{S k,} each point (x, y), according to equation 1 and equation 2 (x ', y') is shifted. For each point in each overlapping region OA _k , each point (x, y) is shifted to (x', y') according to equations 4 and 5. By considering the area OA _k overlap, method 1000 enables a smooth transition between partitions S _k adjacent. Smooth transition will reduce the overlay error that can occur due to a rapid change between compartments S _k adjacent in the first layer.

Although the above is intended for the embodiments described herein, other embodiments and further embodiments may be devised without departing from the basic scope of these embodiments. For example, aspects of the present disclosure may be implemented in hardware or software, or in a combination of hardware and software. One embodiment described herein can be implemented as a program product for use with a computer system. A program (s) of a program product may define the functionality of an embodiment (including the methods described herein) and may be included in a variety of computer-readable storage media. An exemplary computer-readable storage medium is (i) a non-writable storage medium in which information is permanently stored (eg, a CD-ROM drive, flash memory, ROM chip, or any type of solid-state non-volatile semiconductor memory). A read-only memory device in a computer, such as a CD-ROM disk that can be read by, and (ii) a writable storage medium in which modifiable information is stored (eg, a floppy disk in a diskette drive or hard disk drive, or optionally. Types of solid-state random access semiconductor memory), but not limited to these. Such a computer-readable storage medium becomes an embodiment of the present disclosure when accompanied by a computer-readable instruction indicating a function of the disclosed embodiment.

Those skilled in the art will recognize that the above examples are exemplary and not limiting. Substitutions, enhancements, equivalents, and improvements of these examples, which will become apparent to those skilled in the art upon reading the specification and scrutinizing the drawings, are all within the essence and scope of the present disclosure. Intended. Therefore, the following accompanying claims are also intended to include all such modifications, substitutions, and equivalents as being contained within the essence and scope of these teachings.

Claims (15)

This is a method of adjusting the exposure parameters of the substrate according to the overlay error.
Dividing the substrate into a plurality of compartments, each corresponding to one image projection system,
Determining the total overlay error of the first layer deposited on the substrate.
Calculate the partition overlay error for each partition, and for each overlapping region where two or more partitions overlap, using a trend line that is represented by a polynomial of coordinates and gives a coordinate shift for the superposition of the partitions. To determine the total superposition error of the first layer, including calculating the average of the superposition errors of the two or more compartments producing the overlap region.
A method comprising adjusting exposure parameters according to the total overlay error. For each overlapping region where two or more compartments overlap, it is possible to calculate the average of the superposition errors of the two or more compartments that produce the overlapping region.
By measuring the amount of first strain using the first trend line that gives the coordinate shift of the first compartment extending within the overlapping region, the overlay error of the first compartment with respect to the first compartment can be determined. To calculate and
By measuring the amount of the second strain using the second trend line that gives the coordinate shift of the second compartment extending within the overlapping region, the overlay error of the second compartment with respect to the second compartment can be determined. To calculate and
The method according to claim 1, wherein the average value of the superposition error of the first section and the superposition error of the second section is obtained. It is possible to adjust the exposure parameters according to the total overlay error.
The method of claim 2, comprising shifting each coordinate of the overlapping region based on the average of the superposition errors of the two or more compartments producing the overlapping region. Dividing the substrate into a plurality of compartments, each corresponding to one image projection system, can be used.
Determining the origin for each section
The method of claim 1, wherein the origin is used for each compartment to determine the center for each compartment. The method of claim 1, wherein when the points are elements of both the first and second compartments, the points are within the overlapping region. A computer system for adjusting the exposure parameters of a substrate according to the total superposition error.
With the processor
A memory that, when executed by the processor, causes the computer system to divide the substrate into a plurality of compartments, each corresponding to one image projection system.
Determining the total overlay error of the first layer deposited on the substrate.
Calculate the partition overlay error for each partition, and for each overlapping region where two or more partitions overlap, using a trend line that is represented by a polynomial of coordinates and gives a coordinate shift for the superposition of the partitions. To determine the total superposition error of the first layer, including calculating the average of the superposition errors of the two or more compartments that produce the overlap region.
A computer system including a memory for storing instructions for adjusting exposure parameters according to the total overlay error. For each overlapping region where two or more compartments overlap, it is possible to calculate the average of the superposition errors of the two or more compartments that produce the overlapping region.
By measuring the amount of first strain using the first trend line that gives the coordinate shift of the first compartment extending within the overlapping region, the overlay error of the first compartment with respect to the first compartment can be determined. To calculate and
By measuring the amount of the second strain using the second trend line that gives the coordinate shift of the second compartment extending within the overlapping region, the overlay error of the second compartment with respect to the second compartment can be determined. To calculate and
The computer system according to claim 6, wherein the average value of the superposition error of the first section and the superposition error of the second section is obtained. It is possible to adjust the exposure parameters according to the total overlay error.
The computer system according to claim 7, wherein each coordinate of the overlapping region is shifted based on the average of the superposition error of the two or more compartments producing the overlapping region. Dividing the substrate into a plurality of compartments, each corresponding to one image projection system, can be used.
Determining the origin for each section
The computer system according to claim 6, wherein the origin is used for each partition to determine the center for each partition. The computer system of claim 6, wherein if the points are elements of both the first and second compartments, the points are within the overlapping area. When it is a non-transitory computer-readable medium and is executed by a processor
The steps of dividing the substrate into multiple compartments, each corresponding to one image projection system,
A step of determining the total overlay error of the first layer deposited on the substrate.
Calculate the partition overlay error for each partition, and for each overlapping region where two or more partitions overlap, using a trend line that is represented by a polynomial of coordinates and gives a coordinate shift for the superposition of the partitions. In addition, a step of determining the total superposition error of the first layer, which comprises calculating the average of the superposition errors of the two or more compartments producing the overlap region.
A non-temporary computer-readable medium that stores an instruction to cause a computer system to adjust the exposure parameters of a substrate according to the overlay error by performing a step of adjusting the exposure parameters according to the total overlay error. .. For each overlapping region where two or more compartments overlap, it is possible to calculate the average of the superposition errors of the two or more compartments that produce the overlapping region.
By measuring the amount of first strain using the first trend line that gives the coordinate shift of the first compartment extending within the overlapping region, the overlay error of the first compartment with respect to the first compartment can be determined. To calculate and
By measuring the amount of the second strain using the second trend line that gives the coordinate shift of the second compartment extending within the overlapping region, the overlay error of the second compartment with respect to the second compartment can be determined. To calculate and
To obtain the average value of the superposition error of the first section and the superposition error of the second section.
11. The non-transitory computer-readable medium of claim 11. It is possible to adjust the exposure parameters according to the total overlay error.
Shifting each coordinate of the overlapping region based on the average of the superposition errors of the two or more compartments producing the overlapping region.
The non-transitory computer-readable medium of claim 12, comprising. Dividing the substrate into a plurality of compartments, each corresponding to one image projection system, can be used.
Determining the origin for each section
Using the origin for each parcel to determine the center for each parcel
11. The non-transitory computer-readable medium of claim 11. The non-transitory computer-readable medium of claim 11, wherein if the points are elements of both the first and second compartments, the points are within the overlapping area.

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